A vehicular seatbelt device restrains a vehicle occupant using a seatbelt when an emergency situation occurs in the vehicle or when travel conditions are unstable.
In recent years, regulations have been made stating that a child seat is to be used when a young child rides in a vehicle. Therefore, a demand exists for the aforedescribed type of seatbelt device for a vehicle that functions both in instances in which a vehicle occupant is to be restrained in the seat and instances in which a child seat is to be anchored to the seat. When a vehicle occupant is to be restrained, control must be made so that a degree of movement is allowed in normal driving conditions, and so that the restraint on the vehicle occupant is strengthened in the event of an emergency or when travel conditions are unstable. A child seat is itself a structural object and must therefore be attached to the seat and anchored by the belt before the vehicle travels. In such a situation, an assessment must be made as to whether the child seat is anchored to the seat. Such a seatbelt device is disclosed in JP-A-2006-76390.
FIG. 9 hereof shows a seatbelt device disclosed in JP-A-2006-76390, wherein a child seat is faced rearward and provided to a passenger's seat.
In a seatbelt device 210, a transceiving part 212 is provided to a child seat 211, and a transceiving part 214 for determining whether the child seat 211 has been installed is provided to a passenger's seat 213, as shown in FIG. 9. A belt 215 is wrapped around the child seat 211 mounted on the passenger's seat 213, a belt winding device 216 is then driven, and the child seat 211 is anchored by the belt 215. When an ignition key that is inserted into a cylinder of an ignition device is turned past an accessory (ACC) position, the belt winding device 216 is once again driven, and the child seat 211 is securely anchored by the belt.
However, in the seatbelt device 210, the transceiving parts 212, 214 are provided to detect the child seat 211, and are used to detect whether the child seat 211 is present. Merely providing a special sensor for simply detecting the installation of the child seat 211 in order to determine whether the child seat 211 has been installed may make it impossible to suitably anchor the child seat 211 when, for any of a variety of reasons, it cannot be accurately detected whether the child seat 211 is present.
It shall be apparent that the seat belt device is a device for restraining a vehicle occupant as well. Therefore, the seat belt device preferably can determine whether the installed object is a child seat or a vehicle occupant via the operation for restraining the child seat or the vehicle occupant using the belt. In particular, an accurate assessment preferably can be made.
In addition, when slackening or another change in the anchoring state occurs during travel due to any of a variety of reasons while the child seat is anchored, the anchoring state must be promptly returned to a proper state. When the anchoring item is determined to be a child seat, a seat belt device is desirably one that, in the event of an emergency, can issue a control to cancel the initiation of an airbag device or other devices that perform actions in relation to the vehicle occupant.